Accounts

That's a crater in the middle of Derweze, which is a village in Turkmenistan. And it's on fire. It's been on fire for 40 years.

Here is the Wikipedia page;
there's not a ton of information, but I guess enough to give context.
In 1971, this crater formed while some people were drilling, and they
realized that methane was emanating from it. Geologists decided that
burning the gas would be less dangerous than letting it permeate the
atmosphere, and figured that it would burn out in a matter of hours.
It's still burning :) The crater has come to be referred to as the Door To Hell.